Methods and systems for performing geofencing with reduced power consumption

ABSTRACT

A GPS capability of a mobile device may be turned on in order to ascertain an updated current location and then be turned off. Position relative to the geofence may be determined based on the updated current location and a time to fence value that provides an estimate of how soon an individual carrying the mobile device could cross the geofence may be calculated. The GPS capability may be kept turned off for a delay time period that is based at least in part on the calculated time to fence value. After the delay time period, the GPS capability of the mobile device may be turned back on and the cycle of turning on the GPS, ascertaining an updated current location and turning off the GPS may continue. An indication of the position of the mobile device relative to the geofence may be transmitted.

This is a continuation application of co-pending U.S. patent applicationSer. No. 14/938,595, filed Nov. 11, 2015, and entitled “METHODS ANDSYSTEMS FOR PERFORMING GEOFENCING WITH REDUCED POWER CONSUMPTION”, whichis incorporated herein by reference.

TECHNICAL FIELD

The disclosure relates generally to geofencing, and more particularly tomethods and systems for achieving geofencing with reduced powerconsumption.

BACKGROUND

A geofence typically represents a virtual perimeter around a real-worldgeographic area, and the process of using a geofence is often calledgeofencing. A geofence may be a radius or the like around a building orother set location, or can be a predefined set of boundaries like schoolattendance zones or neighborhood boundaries. Geofencing can be used toidentify when a tracked object crosses into or out of a definedgeofence. In some cases, the location of the tracked object may bedetermined using location services of a mobile device, such as asmartphone or other mobile device. In some cases, the location servicesmay include a cellular triangulation capability and/or a GPS capability.Some example geofence application may include notifying parents if theirchild leaves a designated area, tracking when vehicles, employees, orother assets enter or leave a designated area, enabling or disablingcertain geofence enabled equipment when the equipment enters or leaves adesignated area, etc.

Geofencing may also be used in conjunction with building automationsystems. Building automation systems are often used to control safety,security and/or comfort levels within a building or other structure.Illustrative but non-limiting examples of building automation systemsinclude Heating, Ventilation and/or Air Conditioning (HVAC) systems,security systems, lighting systems, fire suppression systems and/or thelike. In some cases, a building automation system may enter anunoccupied mode when the building is expected to be unoccupied and anoccupied mode when the building is expected to be occupied. In oneexample, when the building automation system includes an HVAC system,the building automation system may set a temperature set point of theHVAC system to a more energy efficient setting when in an unoccupiedmode and a more comfortable setting when in an occupied mode. In anotherexample, when the building automation system includes a security system,the building automation system may set the security system to an armedor away state when in an unoccupied mode and an unarmed or home statewhen in an occupied mode. It is contemplated that geofencing may be usedto inform the building automation system as to when the building isexpected to be occupied and unoccupied, and the building automationsystem may respond accordingly.

SUMMARY

The present disclosure pertains generally to geofencing, and in somecases, to building automation systems with geofencing capabilities. Anexample of the disclosure may be found in a method of implementinggeofencing using a mobile device having a GPS capability and beingconfigured to be operably coupled to a building controller. A geofencedefining a region about a building may be set. The GPS capability of themobile device may be turned on in order to ascertain an updated currentlocation of the mobile device, and then be turned off to save power atthe mobile device. A position of the mobile device relative to thegeofence may be determined based on the updated current location and atime to fence value that provides an estimate of how soon an individualcarrying the mobile device could cross the geofence may be calculated.The GPS capability may be kept turned off for a delay time period thatis based at least in part on the calculated time to fence value. Afterthe delay time period, the GPS capability of the mobile device may beturned back on and the cycle of turning on the GPS, ascertaining anupdated current location and turning off the GPS may be repeated. Anindication of the position of the mobile device relative to the geofencemay be transmitted.

Another example of the disclosure may be found in a mobile device havingGPS. The mobile device may include a user interface, a memory and acontroller that is operably coupled to the user interface and to thememory. The memory may store an executable program as well asinformation pertaining to a geofence assigned to a building. Thecontroller may be configured to temporarily turn on the GPS in order todetermine an updated current location of the mobile device, and thenturn the GPS off. The controller may compare the updated currentlocation of the mobile device to the geofence and calculate a time tofence value that indicates a minimum time in which the mobile devicecould cross the geofence. The controller may wait a delay time periodthat is based at least in part on the calculated time to fence valuebefore temporarily turning the GPS on again to determine an updatedcurrent location of the mobile device, and then turn the GPS off. Thecontroller may cause the mobile device to transmit an indication of theupdated current location of the mobile device relative to the geofence.

Another example of the disclosure may be found in a mobile device havinglocation services including a cellular triangulation capability and aGPS capability. The mobile device may include a user interface, a memoryand a controller that is operably coupled to the user interface and tothe memory. The memory may store an executable program as well asinformation pertaining to a geofence assigned to a building. Thecontroller may be configured to turn on at least some of the locationservices in order to determine an updated current location of the mobiledevice. The controller may compare the updated current location to thegeofence and calculate a time to fence value that indicates a minimumtime in which the mobile device could cross the geofence and may thenwait a delay time period that is based at least in part on thecalculated time to fence value before turning on the location serviceson again, and then turn off the location services. The controller maycause the mobile device to transmit an indication of the updated currentlocation of the mobile device relative to the geofence.

While these examples relate to an illustrative geofence application fora building, it is contemplated that the principles disclosed herein canbe used in any suitable geofence application including, but not limitedto, notifying parents if their child leaves a designated area, trackingwhen vehicles, employees, or other assets enter or leave a designatedarea, enabling or disabling certain geofence enabled equipment when theequipment enters or leaves a designated area, etc.

The preceding summary is provided to facilitate an understanding of someof the features of the present disclosure and is not intended to be afull description. A full appreciation of the disclosure can be gained bytaking the entire specification, claims, drawings, and abstract as awhole.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure may be more completely understood in consideration of thefollowing description of various illustrative embodiments of thedisclosure in connection with the accompanying drawings, in which:

FIG. 1 is a schematic view of an illustrative building automationsystem;

FIG. 2 is a schematic view of another illustrative building automationsystem;

FIG. 3 is a schematic view of another illustrative building automationsystem;

FIG. 4 is a schematic view of an illustrative mobile device;

FIG. 5 is a schematic view of another illustrative mobile device; and

FIGS. 6 through 8 are flow diagrams showing illustrative methods thatmay be carried out in accordance with embodiments of the disclosure.

While the disclosure is amenable to various modifications andalternative forms, specifics thereof have been shown by way of examplein the drawings and will be described in detail. It should beunderstood, however, that the intention is not to limit aspects of thedisclosure to the particular illustrative embodiments described. On thecontrary, the intention is to cover all modifications, equivalents, andalternatives falling within the spirit and scope of the disclosure.

DESCRIPTION

The following description should be read with reference to the drawingswherein like reference numerals indicate like elements. The drawings,which are not necessarily to scale, are not intended to limit the scopeof the disclosure. In some of the figures, elements not believednecessary to an understanding of relationships among illustratedcomponents may have been omitted for clarity.

All numbers are herein assumed to be modified by the term “about”,unless the content clearly dictates otherwise. The recitation ofnumerical ranges by endpoints includes all numbers subsumed within thatrange (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).

As used in this specification and the appended claims, the singularforms “a”, “an”, and “the” include the plural referents unless thecontent clearly dictates otherwise. As used in this specification andthe appended claims, the term “or” is generally employed in its senseincluding “and/or” unless the content clearly dictates otherwise.

It is noted that references in the specification to “an embodiment”,“some embodiments”, “other embodiments”, etc., indicate that theembodiment described may include a particular feature, structure, orcharacteristic, but every embodiment may not necessarily include theparticular feature, structure, or characteristic. Moreover, such phrasesare not necessarily referring to the same embodiment. Further, when aparticular feature, structure, or characteristic is described inconnection with an embodiment, it is contemplated that the feature,structure, or characteristic may be applied to other embodiments whetheror not explicitly described unless clearly stated to the contrary.

The present disclosure is directed generally at building automationsystems. Building automation systems are systems that control one ormore operations of a building. Building automation systems can includeHVAC systems, security systems, fire suppression systems, energymanagement systems and/or any other suitable systems. While HVAC systemsare used as an example below, it should be recognized that the conceptsdisclosed herein can be applied to building control systems moregenerally.

A building automation system may include a controller, computer and/orother processing equipment that is configured to control one or morefeatures, functions, systems or sub-systems of a building. In somecases, devices that can be used by individuals to communicate with thecontroller, computer and/or other processing equipment. In some cases, abuilding automation system may include a plurality of components that,in combination, perform or otherwise provide the functionality of thebuilding automation system. A building automation system may be fullycontained within a single building, or may include components that arespread between multiple housings and/or across multiple locations. Insome embodiments, a building automation system, regardless of thephysical location(s) of the components within the building automationsystem, may control one or more building systems within a singlebuilding. In some cases, a building automation system, regardless of thephysical location(s) of the components within the building automationsystem, may control one or more building systems within a plurality ofbuildings, optionally in accordance with a common operating procedureand/or distinct operating procedures for each building as desired.

FIG. 1 is a schematic view of an illustrative building automation system10. The illustrative building automation system 10 includes a server 12that may be configured to communicate with a mobile device 14 and with abuilding controller 16. It will be appreciated that for simplicity, onlya single mobile device 14 is shown, while in many cases the server 12may be configured to communicate directly or indirectly with any numberof mobile devices 14. Similarly, while a single building controller 16is illustrated, in many cases the server 12 may be configured tocommunicate directly or indirectly with any number of buildingcontrollers 16, located in a single building or distributed throughout aplurality of buildings. The server 12 is illustrated as a single,cloud-based server. In some cases, the server 12 may be a single server.In some instances, the server 12 may generically represent two, three ormore servers commonly located or spread between two or more physicallocations. In some cases, the server 12 handles communication with boththe mobile device 14 and the building controller 16. In some instances,as shown for example in FIG. 2, distinct servers may carry out eachcommunications protocol if desired.

In some cases, the mobile devices 14 may communicate with the server 12at least partially through a network such as the Internet, sometimesusing a cell phone network, WiFi network and/or any other suitablenetwork. Likewise, it is contemplated that the building controller 16may communicate with the server 12 at least partially through a networksuch as the Internet, sometimes using a cell phone network, WiFi networkand/or any other suitable network.

FIG. 2 is a schematic illustration of another illustrative buildingautomation system 20. The illustrative building automation system 20includes a first server 22 that may be configured to communicate with amobile device 14 (or multiple mobile devices 14) and a second server 24that may be configured to communicate with a building controller 16 (ormultiple building controllers 16). The first server 22 may be configuredto receive data from the mobile device 14, process the data, and senddata to the mobile device 14 and/or to the second server 24. The secondserver 24 may be configured to receive data from the building controller16, process the data, and send data to the building controller 16 and/orto the first server 22. In some instances, the first server 22 may beconfigured to permit data from the mobile device 14 to pass directlythrough to the building controller 16. In some cases, the second server24 may be configured to permit data from the building controller 16 topass directly through to the mobile device 14. The first server 22 andthe second server 24 may be configured to communicate with each other.In some cases, each of the first server 22 and the second server 24 mayperform a defined function.

It will be appreciated that for simplicity, only a single mobile device14 is shown, while in many cases the first server 22 may be configuredto communicate directly or indirectly with any number of mobile devices14. Similarly, while a single building controller 16 is illustrated, inmany cases the second server 24 may be configured to communicatedirectly or indirectly with any number of building controllers 16,located in a single building or distributed throughout a plurality ofbuildings.

The first server 22 is illustrated as a single, cloud-based server. Insome cases, the first server 22 may be a single server. In someinstances, the first server 22 may generically represent two, three ormore servers commonly located or spread between two or more physicallocations. The second server 24 is illustrated as a single, cloud-basedserver. In some cases, the second server 24 may be a single server. Insome instances, the second server 24 may generically represent two,three or more servers commonly located or spread between two or morephysical locations. In some cases, the first server 22 and the secondserver 24 may, in combination, be considered as representing or forminga building automation server 26.

FIG. 3 is a schematic illustration of a building automation system 30 inwhich a building automation server 26 is configured to communicate witha plurality of buildings 32 as well as a plurality of mobile devices 34.It is contemplated that the building automation server 26 may include asingle server or two or more distinct servers at one or severallocations. The building automation system 30 may serve any desirednumber of buildings. As illustrated, the plurality of buildings 32includes a Building One, labeled as 32A, a Building Two, labeled as 32B,and so on through a Building “N”, labeled as 32N. It will be appreciatedthat the building automation system 30 may include a large number ofbuildings, each in communication with a central (or distributed)building automation server 26. In some cases, each building may beassociated with a unique customer account, as further described below.

As illustrated, each of the plurality of buildings 32 includes abuilding controller and one or more pieces of building equipment. Thebuilding equipment may, for example, be HVAC equipment, securityequipment, lighting equipment, fire suppression equipment, and/or thelike. In particular, the building 32A includes a building controller 36Aand building equipment 38A, the building 32B includes a buildingcontroller 36B and building equipment 38B, and so on through thebuilding 32N, which includes a building controller 36N and buildingequipment 38N. It will be appreciated that while each building isillustrated as having a single building controller and single buildingequipment controlled by the single building controller, in some cases abuilding may have multiple related or unrelated building controllersand/or multiple pieces of related or unrelated building equipment.

The plurality of mobile devices 34 may be considered as being dividedinto a set of mobile devices each associated with a correspondingbuilding. In the example shown, the plurality of mobile devices 34 maybe considered as being divided into a set of mobile devices 40A that areassociated with the building 32A, a set of mobile devices 40B that areassociated with the building 32B, and so on through a set of mobiledevices 40N that are associated with the building 32N. As illustrated,the set of mobile devices 40A includes a first mobile device 42A, asecond mobile device 44A and a third mobile device 46A. The set ofmobile devices 40B includes a first mobile device 42B, a second mobiledevice 44B and a third mobile device 46B and so on through the set ofmobile devices 40N, which includes a first mobile device 42N, a secondmobile device 44N and a third mobile device 46N. This is merelyillustrative, as any number of mobile devices such as smart phones ortablets, may be associated with a particular building, as desired. Eachuser or occupant of a building may have an associated mobile device, ormay have several associated mobile devices. In some cases, a user oroccupant may have a mobile device associated with several differentlocations such as a home, a cabin or a place of work.

Associating a mobile device with a particular building generallyinvolves the individual who uses the particular mobile device. In theexample shown in FIG. 3, a mobile device can communicate with thebuilding automation server 26, and may cause the building automationserver 26 to provide instructions to the building controller that isassociated with the particular mobile device. For example, and in someinstances, a mobile phone with location services activated can be usedto inform the building automation server 26 as to the whereabouts of theuser relative to a geofence defined for the associated building, and insome cases an estimate of how long before the user will arrive at theassociated building. The building automation server 26 may send acommand to the building controller of the associated building to operatethe building equipment in an energy savings manner when all of the usersthat are associated with a particular building are determined to be awayfrom the building (e.g. the building is unoccupied). The buildingautomation server 26 may send a command to the building controller ofthe associated building to operate the building equipment in a comfortmode when all of the users that are associated with a particularbuilding are determined or deemed not to be away from the building (e.g.the building is occupied).

The mobile device need not be a smart phone or tablet. Instead, themobile device may be any GPS enabled tag or module that can be fixed toa person (e.g. building occupant, child, employee) or thing (e.g. car,truck, other equipment). Moreover, while much of the present disclosurerelates to an illustrative geofence application for a building, it iscontemplated that the principles disclosed herein can be used in anysuitable geofence application including, but not limited to, notifyingparents if their child leaves a designated area, tracking when vehicles,employees, or other assets enter or leave a designated area, enabling ordisabling certain geofence enabled equipment when the equipment entersor leaves a designated area, etc.

FIG. 4 is a schematic illustration of an illustrative mobile device 50having GPS capability, schematically illustrated as GPS 52. In someinstances, the mobile device 50 may be considered as being an example ofthe mobile device 14 shown in FIGS. 1 and 2. The mobile device 50 has auser interface 54, a memory 56 and a controller 58 that is operablycoupled to the user interface 54 and to the memory 56. The controller 58may be considered as being operably coupled with the GPS 52 as well. Thememory 56 may be configured to store an executable program as well asinformation pertaining to a geofence that is assigned to a building. Thecontroller 58 may be configured to temporarily turn on the GPS 52 inorder to determine an updated current location of the mobile device 50prior to turning the GPS 52 back off in order to reduce powerconsumption.

In some cases, the controller 58 may be configured to compare theupdated current location of the mobile device 50 to the geofence andcalculate a time to fence value that indicates a minimum time in whichthe mobile device 50 could cross the geofence. The time to fence valuemay be calculated in any of a variety of manners. In some instances, thecontroller 58 may calculate the time to fence value by estimating howsoon an individual carrying the mobile device 50 could cross thegeofence when leaving the building. The controller 58 may calculate thetime to fence value by estimating how soon an individual carrying themobile device 50 could cross the geofence when returning to thebuilding.

The controller 58 may, for example, calculate the time to fence value bydetermining a straight line distance between the updated currentlocation of the mobile device 50 and the building and subtracting aradius of the geofence, and determining the time to fence value based ona predetermined maximum speed that the user carrying the mobile device50 may travel (e.g. 80 mph). In some instances, the controller 58 maycalculate the time to fence value by determining a driving route betweenthe updated current location of the mobile device 50 and a point on thegeofence along the driving route, and determining the time to fencevalue based on the driving route. In some cases, the time to fence valuecalculations may take current traffic and/or road conditions intoaccount, and in some cases, speed limits along the driving route. Insome instances, the controller 58 may be configured to wait a delay timeperiod that is based at least in part on the calculated time to fencevalue before temporarily turning the GPS 52 on again to determine anupdated current location of the mobile device 50, and then turn the GPS52 off. In some cases, the delay time period is linear with thecalculated time to fence value, and represents a particular fraction orpercent thereof. For example, in some cases the delay time period may beabout 80 percent of the calculated time to fence value, or perhaps about90 percent of the calculated time to fence value. In some cases, thedelay time period may be non-linear with the calculated time to fencevalue. For example, the delay time period may be the calculated time tofence value less a predetermined time. In some cases, the delay timeperiod may, for example, be ten minutes less than the calculated time tofence value is one hour or less. The delay time period may be fiveminutes less than the calculated time to fence value if the calculatedtime to fence value is more than one hour. These numerical examples aremerely illustrative.

In some cases, the controller 58 may be configured to calculate ahorizontal dilution of precision (HDOP) value for the current locationindicated by the GPS 52. The HDOP provides an indication of the accuracyof the current GPS reading. For example, if the GPS 52 has locked ontomany GPS satellites, the HDOP may be higher (more accuracy) than if theGPS 52 has only locked onto a few GPS satellites. In another example,the GPS 52 may have a lower HDOP (less accuracy) if the GPS 52 is insideof a building than of the GPS 52 were outside.

In some cases, if the HDOP of the current GPS reading is not very high(lower accuracy), the controller 58 may keep the GPS 52 turned on duringthe delay time period. If the HDOP improves to a level at or above apredetermined HDOP accuracy threshold, the controller 58 may turn theGPS 52 off during the next delay time period. If the HDOP does notimprove, or does not improve sufficiently to reach the predeterminedHDOP accuracy threshold, the controller 58 may make the determinationthat the mobile device 50 is currently in a region with poor GPSservice.

In some cases, if the mobile device 50 is determined to be in a regionwith poor GPS service, the delay time period may be shortened relativeto the calculated time to fence value. Conversely, if the HDOP indicatesthat the mobile device 50 is in a region with good GPS service, thedelay time period may be lengthened relative to the calculated time tofence value in order to further conserve energy at the mobile device 50.

In some cases, the controller 58 may be configured to cause the mobiledevice 50 to transmit an indication of the updated current location ofthe mobile device 50 relative to the geofence. In some cases, thecontroller 58 may be configured to cause the mobile device 50 totransmit an indication of the updated current location of the mobiledevice 50 relative to the geofence each time the location is checkedand/or changed. In some instances, the controller 58 may be configuredto cause the mobile device 50 to transmit the indication of the updatedcurrent location of the mobile device 50 relative to the geofence whenthe updated current location of the mobile device 50 indicates ageofence crossing.

FIG. 5 is a schematic illustration of an illustrative mobile device 60having location services including GPS capability, schematicallyillustrated as GPS 62, and cellular triangulation capability,schematically illustrated as cellular triangulation 64. In someinstances, the mobile device 60 may be considered as being an example ofthe mobile device 14 shown in FIGS. 1 and 2. The illustrative mobiledevice 60 has a user interface 66, a memory 68, and a controller 70 thatis operably coupled to the user interface 66 and to the memory 68. Thecontroller 70 may be considered as being operably coupled with the GPS62 and the cellular triangulation 64. The memory 68 may be configured tostore an executable program as well as information pertaining to ageofence that is assigned to a building. The controller 70 may beconfigured to temporarily turn on at least some of the location servicesin order to determine an updated current location of the mobile device60.

The controller 70 may compare the updated current location to thegeofence stored in the memory 68 and calculate a time to fence valuethat indicates a minimum time in which the mobile device 60 could crossthe geofence. In some cases, the controller 70 may wait a delay timeperiod that is based at least in part on the calculated time to fencevalue before turning on the location services on again, and then turnoff the location services. In some instances, the controller 58 may turnon the cellular triangulation 64 and not the GPS 62 if the calculatedtime to fence value is greater than a predetermined value and may turnon the GPS 62 if the calculated time to fence value is less than thepredetermined value. Typically, cellular triangulation 64 has lessaccuracy than GPS 62, but also consumes far less power. As such, whenthe calculated time to fence value is greater than the predeterminedvalue, and the updated current location is relatively further from thegeofence, the less accurate cellular triangulation 64 may be sufficientto calculate the updated current location. When the calculated time tofence value is less than the predetermined value, and the updatedcurrent location is relatively closer to the geofence, it may bedesirable to use the more accurate GPS 62 to calculate the updatedcurrent location. In some instances, the controller 70 may be configuredto cause the mobile device 60 to transmit an indication of the updatedcurrent location of the mobile device relative to the geofence.

FIG. 6 is a flow diagram showing an illustrative method for implementinggeofencing using a mobile device that has a GPS capability and that isconfigured to be operably coupled to a building controller. As shown atblock 80, a geofence defining a region about a building may be set. TheGPS capability of the mobile device may be turned on, as indicated atblock 82. As seen at block 84, an updated current location of the mobiledevice may be ascertained via the GPS capability and then the GPScapability may be turned off as shown at block 86. A position of themobile device relative to the geofence may be determined based on theupdated current location, as generally indicated at block 88. As shownat block 90, a time to fence value that provides an estimate of how soonan individual carrying the mobile device could cross the geofence may becalculated.

In some instances, calculating the time to fence value includesestimating how soon the individual carrying the mobile device couldcross the geofence when returning to the building. In some cases,calculating the time to fence value includes estimating how soon theindividual carrying the mobile device could cross the geofence whenleaving the building. Calculating the time to fence value may includedetermining a straight line distance between the updated currentlocation of the individual carrying the mobile device and the buildingand subtracting a radius defining the geofence, and determining the timeto fence value based on a predetermined maximum speed value (e.g. 80mph). In some cases, calculating the time to fence value may includedetermining a straight line distance between the updated currentlocation of the individual carrying the mobile device and the closestpoint on the geofence. In some cases, calculating the time to fencevalue may include determining a driving route between the updatedcurrent location of the individual carrying the mobile device and apoint on the geofence along the driving route, and determining the timeto fence value based on the driving route. These are just some examples.

The GPS may remain off for a delay time period that is based at least inpart on the calculated time to fence value, as seen at block 92. In somecases, control may pass back to block 82, and the cycle may continue. Insome cases, however, control may first pass from block 92 to block 94,where the mobile device transmits an indication of its position relativeto the geofence. In some cases, the indication of the position of themobile device relative to the geofence is transmitted when the updatedcurrent location of the mobile device crosses the geofence, and theindication of the position of the mobile device relative to the geofenceindicates a geofence crossing.

FIG. 7 is a flow diagram showing another illustrative method forimplementing geofencing using a mobile device that has a GPS capabilityand that is configured to be operably coupled to a building controller.As shown at block 80, a geofence defining a region about a building maybe set. The GPS capability of the mobile device may be turned on, asindicated at block 82. As seen at block 84, an updated current locationof the mobile device may be ascertained. The horizontal accuracy, orHDOP, of the current location may be checked as seen at block 96. Asdecision block 98, a determination is made as to whether the HDOP isabove a predetermined threshold. If yes, control passes to block 100 andthe GPS capability is turned off. A position of the mobile devicerelative to the geofence may be determined based on the updated currentlocation, as generally indicated at block 102. As shown at block 104, atime to fence value that provides an estimate of how soon an individualcarrying the mobile device could cross the geofence may then becalculated.

In some instances, calculating the time to fence value includesestimating how soon the individual carrying the mobile device couldcross the geofence when returning to the building. In some cases,calculating the time to fence value includes estimating how soon theindividual carrying the mobile device could cross the geofence whenleaving the building. Calculating the time to fence value may includedetermining a straight line distance between the updated currentlocation of the individual carrying the mobile device and the buildingand subtracting a radius defining the geofence, and determining the timeto fence value based on a predetermined maximum speed value (e.g. 80mph). In some cases, calculating the time to fence value may includedetermining a straight line distance between the updated currentlocation of the individual carrying the mobile device and the closestpoint on the geofence. In some cases, calculating the time to fencevalue may include determining a driving route between the updatedcurrent location of the individual carrying the mobile device and apoint on the geofence along the driving route, and determining the timeto fence value based on the driving route. These are just some examples.

The GPS may remain off for a delay time period that is based at least inpart on the calculated time to fence value, as seen at block 106. Insome cases, control may pass back to block 82, and the cycle maycontinue. In some cases, however, control passes from block 106 to block114, where the mobile device transmits an indication of its positionrelative to the geofence. In some cases, the indication of the positionof the mobile device relative to the geofence is transmitted when theupdated current location of the mobile device crosses the geofence, andthe indication of the position of the mobile device relative to thegeofence indicates a geofence crossing.

Returning back to decision block 98, if the HDOP is not above apredetermined threshold, control passes to block 108. Block 108 keepsthe GPS on during the subsequent delay period in an attempt to get amore accurate reading on the current location. A position of the mobiledevice relative to the geofence may then be determined based on theupdated current location, as generally indicated at block 110. As shownat block 112, a time to fence value that provides an estimate of howsoon an individual carrying the mobile device could cross the geofencemay be calculated. In some cases, control may pass back to block 84, andthe cycle may continue. In some cases, however, control passes fromblock 112 to block 114, where the mobile device transmits an indicationof its position relative to the geofence. In some cases, the indicationof the position of the mobile device relative to the geofence istransmitted when the updated current location of the mobile devicecrosses the geofence, and the indication of the position of the mobiledevice relative to the geofence indicates a geofence crossing.

FIG. 8 is a flow diagram showing another illustrative method forimplementing geofencing using a mobile device that has a GPS capabilityand that is configured to be operably coupled to a building controller.As shown at block 80, a geofence defining a region about a building maybe set. The GPS capability of the mobile device may be turned on, asindicated at block 82. As seen at block 84, an updated current locationof the mobile device may be ascertained via the GPS capability and thenthe GPS capability may be turned off as shown at block 86. A position ofthe mobile device relative to the geofence may be determined based onthe updated current location, as generally indicated at block 88. Asshown at block 90, a time to fence value that provides an estimate ofhow soon an individual carrying the mobile device could cross thegeofence may be calculated.

In some instances, calculating the time to fence value includesestimating how soon the individual carrying the mobile device couldcross the geofence when returning to the building. In some cases,calculating the time to fence value includes estimating how soon theindividual carrying the mobile device could cross the geofence whenleaving the building. Calculating the time to fence value may, forexample, include determining a straight line distance between theupdated current location of the individual carrying the mobile deviceand the building and subtracting a radius defining the geofence, anddetermining the time to fence value based on a predetermined maximumspeed value (e.g. 80 mph). In some cases, calculating the time to fencevalue may include determining a straight line distance between theupdated current location of the individual carrying the mobile deviceand the closest point on the geofence. In some cases, calculating thetime to fence value may include determining a driving route between theupdated current location of the individual carrying the mobile deviceand a point on the geofence along the driving route, and determining thetime to fence value based on the driving route. These are just someexamples.

The GPS may remain off for a delay time period that is based at least inpart on the calculated time to fence value, as seen at block 92. In somecases, control may pass back to block 82, and the cycle may continue. Insome cases, however, control may be passed from block 92 to block 94,where the mobile device transmits an indication of its position relativeto the geofence. In some cases, the indication of the position of themobile device relative to the geofence is transmitted when the updatedcurrent location of the mobile device crosses the geofence, and theindication of the position of the mobile device relative to the geofenceindicates a geofence crossing. In some cases, the time to fence valuemay be transmitted to a building controller so that the buildingcontroller can regulate operation of a building system in accordancewith the time to fence value as seen at block 116.

Those skilled in the art will recognize that the present disclosure maybe manifested in a variety of forms other than the specific embodimentsdescribed and contemplated herein. Accordingly, departure in form anddetail may be made without departing from the scope and spirit of thepresent disclosure as described in the appended claims.

What is claimed is:
 1. A mobile device comprising: a user interface; amemory for storing an executable program, the memory also storinginformation pertaining to a geofence assigned to a building; acommunications module; location services including a lower powerlocation capability that consumes power when activated and a higherpower location capability that consumes more power than the lower powerlocation capability when activated, each providing an updated currentlocation of the mobile device when activated; a controller operablycoupled to the user interface, the memory, the communications module,and the location services, the controller configured to: compare theupdated current location provided by the location services to thegeofence and determine when the mobile device has crossed the geofenceindicating a geofence crossing event; upon determining a geofencecrossing event, cause the mobile device to communicate the geofencecrossing event to a building controller at least in part via thecommunications module of the mobile device so that the buildingcontroller can regulate operation of a building system in response tothe geofence crossing event; when the mobile device is more than athreshold from the geofence, use the lower power location capabilitymore often than the higher power location capability to provide theupdated current location of the mobile device; and when the mobiledevice is less than the threshold from the geofence, use the higherpower location capability to provide the updated current location of themobile device.
 2. The mobile device of claim 1, wherein the lower powerlocation capability comprises a cellular triangulation capability. 3.The mobile device of claim 1, wherein the higher power locationcapability comprises a GPS capability.
 4. The mobile device of claim 1,wherein the lower power location capability comprises a cellulartriangulation capability and the higher power location capabilitycomprises a GPS capability.
 5. The mobile device of claim 1, wherein thethreshold corresponds to a distance.
 6. The mobile device of claim 1,wherein the threshold corresponds to a time.
 7. The mobile device ofclaim 1, wherein the threshold corresponds to a predetermined TIME TOFENCE threshold, and the controller is configured to: use the updatedcurrent location of the mobile device to determine a TIME TO FENCEvalue, wherein the TIME TO FENCE value is an estimate of a minimumlength of time that it would take for an individual carrying the mobiledevice to cross the geofence; use the lower power location capability ofthe mobile device more often than the higher power location capabilitywhen the determined TIME TO FENCE value is greater than thepredetermined TIME TO FENCE threshold; and use the higher power locationcapability of the mobile device when the determined TIME TO FENCE valueis less than the predetermined TIME TO FENCE threshold.
 8. Anon-transitory computer-readable storage medium with an executableprogram stored thereon, wherein the executable program is configured toinstruct a mobile device, having a user interface with a display, acommunications module, a memory, and location services including a lowerpower location capability that consumes power when activated and ahigher power location capability that consumes more power than the lowerpower location capability when activated, each for providing an updatedcurrent location of the mobile device when activated, to perform thefollowing: comparing the updated current location provided by thelocation services to a geofence stored in the memory of the mobiledevice and determining when the mobile device has crossed the geofenceindicating a geofence crossing event; upon determining a geofencecrossing event, causing the mobile device to communicate the geofencecrossing event to a building controller at least in part via thecommunications module of the mobile device so that the buildingcontroller can regulate operation of a building system in response tothe geofence crossing event; and when the mobile device is more than athreshold from the geofence, using the lower power location capabilitymore often than the higher power location capability to provide theupdated current location of the mobile device; and when the mobiledevice is less than the threshold from the geofence, using the higherpower location capability more often than the lower power locationcapability to provide the updated current location of the mobile device.9. The non-transitory computer-readable storage medium of claim 8,wherein the lower power location capability comprises a cellulartriangulation capability.
 10. The non-transitory computer-readablestorage medium of claim 9, wherein the higher power location capabilitycomprises a GPS capability.
 11. The non-transitory computer-readablestorage medium of claim 8, wherein when the mobile device is less thanthe threshold from the geofence, using the higher power locationcapability and not using the lower power location capability to providethe updated current location of the mobile device.
 12. Thenon-transitory computer-readable storage medium of claim 8, wherein thethreshold corresponds to a distance.
 13. The non-transitorycomputer-readable storage medium of claim 8, wherein the thresholdcorresponds to a time.
 14. The non-transitory computer-readable storagemedium of claim 8, wherein the threshold corresponds to a predeterminedTIME TO FENCE threshold, and the executable program is configured toinstruct the mobile device to perform the following: using the updatedcurrent location of the mobile device to determine a TIME TO FENCEvalue, wherein the TIME TO FENCE value is an estimate of a minimumlength of time that it would take for an individual carrying the mobiledevice to cross the geofence; using the lower power location capabilityof the mobile device more often than the higher power locationcapability when the determined TIME TO FENCE value is greater than thepredetermined TIME TO FENCE threshold; and using the higher powerlocation capability of the mobile device when the determined TIME TOFENCE value is less than the predetermined TIME TO FENCE threshold. 15.A method, comprising comparing an updated current location of a mobiledevice provided by a location services of the mobile device to ageofence stored by the mobile device, wherein the location servicesincludes a lower power location capability that consumes power whenactivated and a higher power location capability that consumes morepower than the lower power location capability when activated, anddetermining when the mobile device has crossed the geofence indicating ageofence crossing event; upon determining a geofence crossing event,causing the mobile device to communicate the geofence crossing event toa building controller so that the building controller can regulateoperation of a building system in response to the geofence crossingevent; when the mobile device is more than a threshold from thegeofence, using the lower power location capability of the locationservices more often than the higher power location capability of thelocation services of the mobile device; and when the mobile device isless than the threshold from the geofence, using the higher powerlocation capability to provide the updated current location of themobile device.
 16. The method of claim 15, wherein the lower powerlocation capability comprises a cellular triangulation capability. 17.The method of claim 15, wherein the higher power location capabilitycomprises a GPS capability.
 18. The method of claim 15, wherein thelower power location capability comprises a cellular triangulationcapability and the higher power location capability comprises a GPScapability.
 19. The method of claim 15, wherein the thresholdcorresponds to a distance.
 20. The method of claim 15, wherein thethreshold corresponds to a predetermined TIME TO FENCE threshold, andthe method further comprises: using the updated current location of themobile device to determine a TIME TO FENCE value, wherein the TIME TOFENCE value is an estimate of a minimum length of time that it wouldtake for an individual carrying the mobile device to cross the geofence;using the lower power location capability of the mobile device moreoften than the higher power location capability when the determined TIMETO FENCE value is greater than the predetermined TIME TO FENCEthreshold; and using the higher power location capability to provide theupdated current location of the mobile device when the determined TIMETO FENCE value is less than the predetermined TIME TO FENCE threshold.